1. Field of the Invention
The present invention relates to applications of microRNA-195, and in particular relates to applications of microRNA-195 with regard to atherosclerosis treatment and detection.
2. Description of the Related Art
MicroRNAs (miRNAs) are single-stranded RNA molecules of about 21-23 nucleotides in length, which regulate gene expression. MiRNAs are first transcribed as a pri-miRNA with a cap and a poly-A tail and then processed to short, 70-nucleotide stem-loop structures known as pre-miRNA in a cell nucleus. The pre-miRNAs are then processed to mature miRNAs in the cytoplasm. A mature miRNA is complementary to a part of one or more messenger RNAs (mRNAs). Animal miRNAs are usually complementary to a site in the 3′ untranslated region (UTR). Annealing of the miRNA to the mRNA inhibits protein translation, but sometimes facilitates cleavage of the mRNA.
MiRNAs are important regulators for cell growth, differentiation, and apoptosis (Costinean S, et al. Proc Natl Acad Sci USA. 2006; 103:7024-7029, Ambros V. 2004; 431:350-355 and Hwang H W, et al. Br J Cancer 2006; 94:776-780). Therefore, miRNAs may be important for normal development and physiology of cells. Consequently, dysregulation of miRNA may lead to human diseases. In this respect, an exciting research area is the role of miRNAs in cancer, given that cell dedifferentiation, growth, and apoptosis are important cellular events during the development of cancer. MiRNAs are currently thought to function as both tumor suppressors and oncogenes (Esquelq-Kerscher A, et al. Nature Reviews Cancer. 2006; 6:259-269). Although miRNAs are expressed in the cardiovascular system (Lagos-Quintana M, et al. Curr Biol. 2002; 12:735-739), the role of miRNAs in atherosclerotic diseases are almost completely unknown. However, few studies have revealed the importance of miRNAs in cardiomyopathies (van Rooij E, et al. Proc Natl Acad Sci U S A. 2006; 103:18255-18260). Nevertheless, the role of miRNAs in atherosclerotic diseases has yet to be fully investigated.
A tissue-specific expression is one important characteristic of miRNA expression. Specifically, one miRNA may be highly expressed in one tissue but have no or low expression in other tissues (Lagos-Quintana M, et al. Curr Biol. 2002; 12:735-739). A recent study using a rat model showed that 140 out of 180 tested miRNAs were expressed in the rat carotid arteries and 49 of the 140 were highly expressed in the rat normal arteries (Ji R, et al. Circ Res. 2007; 100:1579-1588).